Multiple compartment refrigerator



Dec. 27, 1938. L. J. BRONAUGH T AL 2,141,459

MULTIPLE COMPARTMENT REFRIGERATOR Filed Jan. 50, 1934 2 Sheets-Sheet 1 INVENTOR L../. BRONHUGH.

7T POTTER.

Dec. 27, 1938. 1.. J. BRONAUGH El AL 2,141,459

MULTIPLE COMPARTMENT REFRIGERATOR Filed Jan. 30, 1934 2 Sheets-Sheet 2 INVENTOR 1...! BFPONAUG/v.

BY W ATTORNEY Patented Dec. 27, 1938 UNITED STATES PATENT OFFICE MULTIPLE COMPARTMENT REFRIGERATOR New York Application January 30, 1934, Serial No. 708,936

2 Claims.

Our invention relates to improvements in mechanical refrigerators, particularly refrigerators adapted for domestic use as distinguished from commercial installations.

The present application is a continuation in part of our application Serial No. 528,940, filed April 9, 1931, and has for an object to provide a novel control apparatus for multi-chambered refrigerator cabinets of the general character described in our copending application Serial -No. 516,032, filed February 16, 1931.

Another object of the invention is to provide a multi-chambered refrigerating cabinet with novel means for maintaining different normal temperatures in the several chambers.

In said copending application Serial No. 516,032, we described a system comprising a pair of thermally separated chambers with a refrigerating element in each, the two elements being connect,- ed in series so that heat pumped from one chamber had to pass through the refrigerating element in the other chamber, thereby maintaining a lower temperature in one chamber than in the other. The present invention has for an object to provide a system of refrigeration in which the elements are connected in parallel but with the cooling effect of said elements being so related as to produce a predetermined normal diiference of temperature in the two chambers.

Other objects of our invention will appear in the following description of several embodiments thereof and thereafter the novelty and scope of the invention will be pointed out in the claims.

In the accompanying drawings;

Figure 1 is a view iii-vertical section of a multi-chambered cabinet cooled by a dry system and provided with two refrigerating elements of different size or heat absorbing capacity but operating at the same pressure or temperature;

Fig. 2 is a view similar to Fig. 1, but in which the refrigerating elements differ in pressure or temperature rather than heat absorbing capacity;

Fig. 3 is a view in longitudinal section of a typical pressure control valve such as employed in the structure shown in Fig. 2;

Fig. 4 is a view similar to Fig. 1 illustrating a wet system with refrigerating elements which differ from each other in size or heat absorbing capacity rather than in operating pressure or temperature;

Fig. 5 is a view similar to Fig. 4 but in which the refrigerating elements differ from each other in pressure or temperature rather than in heat absorbing capacity; and

Fig. '6 is a view in section taken on the line 6-6 of Fig. 4.

Before proceeding with a detailed description of the various embodiments illustrated we would explain that our refrigerator comprises a cabinet having, preferably, three refrigerating chambers. One of these chambers constitutes a main food chamber, in which is maintained a temperature low enough to preserve food but above the freezing point so that the food cannot be spoiled or injured by freezing. This chamber is cooled by a freezing element of the non-frosting type so that it will not be necessary to defrost the element. Since there is no loss of moisture by freezing and no means are provided for escape of moisture from the chamber the atmosphere in this chamber is maintained at close to its saturation point and the foods therein are not dried out. Hereinafter this main chamber will be called the cooling chamber, Thermally insulated from the cooling chamber is a second chamber, hereinafter called the cold storage chamber. Here a dry atmosphere is maintained that is far below the freezing point, In this chamber may be stored foods which will not suffer by being frozen and which, therefore, will keep for a long time. The cold storage chamber is thermally connected with another chamber known'as the freezing chamber in which an even lower temperature is maintained for the purpose of freezing ice cubes, desserts, etc. In actual practice we have found that-it is desirable to maintain a temperature of about 40 degrees Fahrenheit in the cooling chamber and a temperature below zero Fahrenheit in the freezing chamber, while the temperature in the cold storage chamber may be a. few degrees warmer than that in the freezing chamber. Because of the very low temperature in the freezing and cold storage chambers such moisture as is condensed out of the atmosphere there in, is frozen into a fine snow which may be brushed or scraped out from time to time without the necessity of arresting refrigeration for defrosting purposes.

Referring now to Figure 1, we show a cabinet 36 having a compartment 35 at the bottom thereof in which a heat pumping unit is located. At the top of the cabinet is a cooling chamber 31 while intermediate between chamber 31 and compartment 35 is a cold storage chamber 38. The latter is separated from the compartment 35 by a thick partition wall packed with suitable insulation material, while a thinner wall of insulation 3| separates chamber 38 from chamber 31. The chambers are also protected from inflow of heat from the outside atmosphere by means of sidewalls 32 and 33 packed with insulation material, and it will be observed that the wall 32 surrounding chamber 38 is thicker than the wall 33 surrounding chamber 31. Also the insulating top wall 34 of chamber 31 is of substantially the same'thickness-as'the side wall 33. The heat-flow resisting qualities of the several walls are proportioned substantially to the desired normal difference of temperature on opposite sides thereof.

' The refrigerator shown in Fig. 1 uses a so-called dry system of refrigeration.

48. pipe 4|, while the warmed and expanded refrigerant escapes through a pipe 42. The freezing element 39 is formed with cells 39a for ice trays and other receptacles, and these cells collectively form the freezing chamber of the refrigerator. It will be observed that the freezing unit 39 occupies one side of the chamber 38 and extends from top to bottom of'the chamber so that the cooling of chamber 38 is effected by exposure of only one side of said unit. Obviously, therefore, the temperature of the cold storage chamber 38 will not be as low as that of the cells 39a. constituting the freezing chamber. The cold storage chamber 38 may be provided with shelves 43 and the cooling chamber with shelves 44.

The heat pumping unit shown in the compartment 35 comprises a base 45 containing a receiver 46. On the base are mounted a motor 41 and a compressor 48 which is driven by said motor through a belt drive 49. A suction line 58 for expanded gaseous refrigerant leads to the compressor 48 and from the compressor 48 a discharge line 53 passes into a separator 54 and thence is continued through a condenser 55 to the receiver 46. From the receiver 46 extends the usual liquid'refrigerant feed line 56.

In the cooling chamber 31 there is a non-frosting expansion coil 51 which is fed with refrigerant from the feed line 56 through an adjustable expansion valve 59, the opposite end of the coil being connected to the suction line 56. Similarly the expansion coil 46 is connected by the pipe 4| to the liquid feed line 56 through an adjustable expansion valve 68 while the pipe 42 is connected to the suction line. Thus, the two refrigerating elements" and 51 are connected in parallel.

The control of the refrigerator depends upon the temperature in the chamber -31 because it is important to keep the temperature here between fairly close limits above the freezing point and below that at which the food might spoil. For this reason, a thermostatic electric switch 5| is located in the chamber 31 which serves to control the circuit 52 of the motor 41. A suitable fitting 52a is provided in the cabinet through which connection may be made to a source of power (not shown) for energizing theinotor cirouit.

The expansion valves 59 and 60 are preferably adjusted to the same setting, but a difference in cooling effect is obtained by relatively proportioning the elements so that element 51 has much less heat-absorbing capacity than that of element 39. A baiile 6| may be provided to aid in circulation of air about the element 51 and also to prevent moisture of condensation from dripping on the food.

Attention has been drawn to the fact that the chamber 31 has a lesser thickness of insulation In the chamber 38 there is a freezing unit 38 in the form of a brinetank through which passes an, expansion coil This coil is fed with refrigerant through a' from the outside atmosphere than that of chamber 38. It is intended that there shall be a greater inflow of heat into chamber 31 than into chambers 38 and 3911 so that the chamber 31 will always be warmer than the cold storage and freezing chambers. The inflow of heat through the walls of thechamber 31 causes periodic operation of the heat pumping unit under control of thethermostatic switch 5|, and at each operation of the heat pumping unit the desired'relative temperatures of the several chambers is reestablished.

The construction shown in Fig. 2 is very similar to that shown in Fig. 1 and like parts are indicated with the same reference numerals. In place of the coil 51 there is a much larger nonfrosting coil 62. The temperature of the coil 62 however is much higher than that of the freezing element 39, this difference oftemperature being obtained by providing a pressure control valve 65 in the suction line of the element 62. This valve may be of any standard construction, a typical form being shown in section in Fig. 3. It comprises an inlet chamber under control of the needle valve 10. The needle valve which is secured to a bellows 1| is urged downward to closed position by a spring 12. When the pressure in the chamber 68 rises above a predetermined minimum the bellows is forced upward against the pressure of the spring 12, opening the valve 18 and permitting a flow of fluid between the chambers 68 and 69. Thus the pressure in the refrigerating element 62 and hence its cooling effect is controlled by the pressure of the spring 12.

It will be observed that the essential difference between the two embodiments of our invention so far described is that in the first case, namely that shown in Fig. 1, the relative cooling effect of the refrigerating elements depends entirely upon their relative size or heat absorbing capacity, while in the second case, the relative cooling effect depends uponthe relative pressure at which they operate, a greater pressure drop being permitted in element 39 than in element 62.

The structures shown in Figs. 4 and 5 differ from those shown in Figs. 1 and 2 respectively in employing a"wet rather than a dry system of refrigeration. The coil 40' of the refrigerating element 39 shown in Fig. 4, is connected in the usual manner to a float chamber 16. The ele- -ment 39' like thecorresponding element 39 is The float chamber 16 is fed with liquid refrigerant from the feed pipe 56 through inlet pipe 4i, and gaseous refrigerant is drawn out through pipe 42 into the suction line 50. The inlet of refrigerant into the chamber 16 is controlled {by the usual valve 14 (Fig. 6) operated by a float 15, said valve being adapted to open when the liquid 11 in the chamber 16 drops below a predetermined level. The cooling chamber 31 is provided with a non-frosting coil 13 connected to a float chamber 16a similar to the chamber 16. The two refrigerating elements are connected in parallel to the pipe lines 58 and 56 and the same pressure conditions are maintained in each of the chambers 16. However, because of the difference in refrigerating area of the two elements, the chamber 31 will be maintained at a higher cooling temperature than the chamber 38. With this construction no thermostatic switch is required in the chamber 31, but the operation of the motor 41 is controlled entirely by a pressure operated switch 19 in the suction limit). This switch which may if of said system employing volatile fluid as the sole be of standard type. controls the circuit the -motor 4i.

The construction shown in Fig. 5 differs from that shown in Fig. 4 only in the fact that a different pressure is maintained in the two refrigerating elements, and the cooling eifect does not depend upon relative dimensions of said elements but on the fact that the refrigerating element 18 in chamber 311s maintained at a higher temperature than that of the element 40. To this end a pressure regulating valve 80 is provided in the suction line 50 between the two elements. This valve rrnlaysbe similar in construction to that shown in While the four alternative forms herein described may appear to be quite diflerent, in reality their functioning is quite similar, and they differ from each other only in details by variations in type of refrigerating coils employed whether they 24) be of the wet" or the dry' system or whether their differential refrigerating eflect is obtained by diflerence of proportions or difference of pressure.

we claim:

1. A household refrigerator comprising a cabinet having two food chambers thermally insulated from each other and from the outside atmosphere, a refrigerating system in the cabinet thermally proportioned to cool one of the cham- 30 bers to a sharp freezing temperature while cooling the other chamber to a refrigerating temperature above the freezing point of water without exposing a frosting surface in the latter chamber,

refrigerant therein and comprising a refrigerant circuit and a pair of expanders in unrestricted communication with each other and connected in parallel in said circuit and disposed in said chambers respectively, and control means constructed and arranged to suspend operation of the refrigerating system when the surface temperature of the expander in the warmer chamber falls to a predetermined degree above the freezing point of water and to restart operation of the refrigerating system when said surface temperature rises above a predetermined maximum.

2. A household refrigerator comprising a cabinet having two chambers thermally insulated from each other, means for maintaining the temperature in one chamber above freezing and within a very narrow temperature range, means for maintaining the other compartment always well below freezing but within a relatively wide temperature range, said means including refrigerant expanders in the respective chambers connected in parallel, the expander in the warmer chamber presenting a relatively large nonfrosting heat exchange surface to the air in said chamber, the expander in the low temperature chamber presenting a relatively small heat exchange surface and means responsive substantially to the surface temperature of the expander in the warmer chamber for stopping circulation of refrigerant through both expanders.

LEWIS J. BRONAUGH.

THOMAS I. POTTER. 

